Process and device for packaging products

ABSTRACT

Products consisting, for example, of stacks of articles having a flattened shape, such as sanitary articles, are packaged inside the corresponding bags, by providing a device which keeps the aforesaid bags open while a pusher element is pushing the products inside the bags. Once the pushing movement has been completed, the bags containing the products are left free to advance towards a closing station, thus disengaging the pusher element. In this way, the aforesaid pusher element is prevented from advancing inside the closing station and from being subsequently backed off from the said station. Preferably, the closing station is made by means of an orientable structure, which enables sealing lines of the packages to be made that are oriented both in the horizontal direction and in the vertical direction, so adapting to the orientation of the bags fed onto the device.

[0001] The present invention relates to the packaging of products.

[0002] In certain processes of this type known in the art, a single pusher element is generally used both for inserting the products inside a bag and for getting the bag itself with the products inserted therein to advance towards a station or stations that carry out closing of the bag, generally with the formation of end bellows-like parts (i.e. so-called gussets).

[0003] A solution that is on the whole similar to the one just referred to is known from U.S. Pat. No. 5,860,270. In this solution, the bags, which are already filled with the corresponding products, are made to advance towards the closing region by means of pusher elements that penetrate into the bags.

[0004] Although these solutions are aimed at optimizing operations of intervention on the products and on the bags that receive them, they come up, above all as regards speed of operation, against an intrinsic limit due to the fact that the closing station cannot be activated to proceed to closing of the package until the pusher element has drawn back from the package so as not to interfere with operation of the closing station itself.

[0005] The solutions according to the prior art can moreover present further drawbacks and/or limitations essentially linked to the fact that:

[0006] the closing station is able to operate only in a single direction; i.e., it is able to form package-sealing lines that necessarily extend in a single direction which cannot be modified. At least in certain operating conditions, the products that are to be packaged (generally consisting of a stack of products having a flattened shape) must then be subjected to a general movement of rotation about an axis parallel to the axis that defines their direction of advance, this operation being one which moreover leads, more often than not, to a misalignment of the products with respect to the ideal working axis of the machine;

[0007] both the action of the pusher element and the action of the closing station may exert on the package undesired stresses that are liable, for instance, to cause the package to assume an undesired swelled-up appearance;

[0008] the above-mentioned stresses may then cause the end bellows-like areas of the package to be closed in an irregular and/or asymmetrical way, with the risk of impairing, for example, proper visibility and legibility of graphical indications appearing on these parts of the package.

[0009] The purpose of the present invention is to provide a solution that is able to overcome the problems outlined above.

[0010] According to the present invention, the above purpose is achieved thanks to a process having the characteristics specifically recalled in the ensuing claims.

[0011] The invention also relates to the corresponding device.

[0012] The invention will now be described, purely by way of non-limiting example, with reference to the attached drawings, in which:

[0013]FIGS. 1 and 2 illustrate, in two different perspective views, a package that may be made according to the invention;

[0014]FIG. 3 is an overall perspective view of a device according to the invention;

[0015]FIG. 4 is a side elevation of the device represented in FIG. 3; and

[0016]FIG. 5 basically corresponds to a view/section along the line V-V of FIG. 4.

[0017] In the example of embodiment here illustrated, which, it is recalled, is merely an example, the solution according to the invention is designed to enable the making of packages comprising:

[0018] an article having an approximately parallelepepidal shape; and

[0019] a wrapper made of a film or sheet material E, which basically resembles a bag having a first end and a second end, and being provided, at least at the second end, with a sealing line S2, with the possible presence at one or both of the ends of respective bellows-like formations B1, B2.

[0020] According to the specific modes of fabrication adopted, the type of wrapper may, however, take on an extremely wide range of forms, and thus be markedly different from the one illustrated herein.

[0021] For example, the first end of the wrapper (i.e., the one opposite to the second end which is designed to be closed by the sealing line S2) may also be closed at a respective sealing line S1, which is represented by a dashed line in FIGS. 1 and 2. This solution applies typically in the cases where the wrapper is formed starting from a tubular length of sheet or film material.

[0022] Other possible solutions envisage, instead, that the first end of the wrapper will be formed by folding a plane length of sheet material into a U shape. In this case, the sealing line S1 is, of course, not present.

[0023] Again associated to the first end of the wrapper E there may be one or more slip-knot elements, which enable the package to be closed after it has been opened for the first time by being torn at the said end.

[0024] What has been said above regarding the possibility of having types of wrapper E that are very different from one another also applies to the possible presence of the bellows-like formations B1 and B2.

[0025] In the example of embodiment illustrated, the bellows-like formations B2 associated to the sealing line S2 extend in a direction that is transverse to the package itself, whilst the bellows-like formations B1 generally extend in a direction that is longitudinal with respect to the development of the package. This solution may usually be found in wrappers in which the first end is formed already closed by bending a sheet element to form a U (hence, without giving rise to the sealing line S1).

[0026] Instead, in the case where the formation of the sealing line S1 is envisaged, the corresponding bellows-like formations B1 also usually extend in a direction transverse to the package.

[0027] In any case, as will be even better appreciated from the ensuing description, the specific modalities of fabrication of the wrapper E in no way impose conditions as regards the embodiment of the solution according to the invention.

[0028] The proposed solution is in fact able to operate on any type of wrapper that may be configured as a bag which will be able to receive, within it, at least one article that is slid into the bag E starting from one end (the second end, with reference to the terminology adopted for describing FIGS. 1 and 2), causing it to advance towards the opposite end, i.e., the first end. The above applies whatever the way in which this first end has been closed; rather, the solution according to the invention makes it possible to operate even on bags E that are still altogether open at the first end, which is designed to define the bottom region of the package.

[0029] In the case of the example here illustrated, which is not to be interpreted as being in any way a limitation of the scope of the invention, the article in question is, in fact, made up of a stack of products P, each of which has a generically flattened shape.

[0030] The products comprised in the stack of products P may be, for example, sanitary products, such as absorbent sanitary pads, nappy pants, panty-liners, etc., which are possibly already placed inside respective bag-like packs.

[0031] A stack of products P of the type described may be made, for example, using the grouping device described in EP-A-0 943 562.

[0032] For this reason (and recalling that the present description is provided purely by way of example which in no way limits the scope of the invention), the device according to the invention, designated as a whole by the reference number 1 in FIGS. 3 and 4, is represented as being set ideally cascaded to a grouping device K of the type described in the European patent just cited. This known grouping device is partially visible in the parts furthest towards the right in FIGS. 3 and 4.

[0033] This particular solution, which has a preferential but not imperative character, is dictated by the fact that, in a possible embodiment of the invention, it is envisaged that the wrappers E previously described are initially formed (in a way of itself known, using a device not specifically illustrated in the drawings) in the form of bags E already closed at one end.

[0034] The bags E thus pre-formed are fed towards the device 1. The latter carries out insertion, within the bags, of the stacks of products P, starting from the second end, and then proceeds to the formation of the other sealing line S2 and of the bellows-like formations B2 associated thereto.

[0035] For this reason, in the device 1, starting from the end thereof set upstream (i.e., the end facing the grouping device K, in the example of embodiment herein illustrated), it is possible to distinguish:

[0036] a pushing or insertion station 2, in which the stacks of products P are inserted inside the bags E (coming from the corresponding formation station, of which the output stage alone, designated by F, is represented in FIG. 3), starting from the second end of the bags opposite to the first end, which is already closed; and

[0037] a package-closing station, designated as a whole by 3, where the bags E, with the products P inserted inside them, are finally closed with the formation of the sealing lines S2.

[0038] The stations 2 and 3 are hence set in cascaded fashion in the general direction of movement of the products P which (as viewed in FIGS. 3 and 4) advance through the device 1 from right to left.

[0039] In the sequel of the present description it will be assumed that the said direction of feed is horizontal or substantially horizontal.

[0040] At the end that is furthest upstream of the device 1, hence at the input end of the pushing station 2, the stacks of products P coming from the grouping device K are made to advance on a conveyor 4. This is preferably a motor-driven conveyor of a known type, comprising, for example, a plurality of motor-driven belts which together define a line for conveying the products P, the said line having a general channel-like conformation.

[0041] This solution (which, on the other hand, is not imperative) makes it possible to keep the products of the stacks of products P in a condition where they are set alongside one another and, preferably in a condition of compression of the stack of products P obtained, according to the modalities described in detail in EP-A-0 943 562, at the output from the device K.

[0042] Within the conveyor 4 there is present an area 5 (defined, for example, by a discontinuity in a side wall of the conveyor 4 itself) designed to enable feed of the pre-formed bags E coming from the station F towards the flow of stacks of products P. Alternatively, feed of the bags E may simply be from above, exploiting the general channel-like conformation of the conveyor 4.

[0043] In particular, it is envisaged that the pre-formed bags E may be fed towards the area 5 in at least two different possible conditions of orientation orthogonal to one another.

[0044] A first condition of orientation (the one to which explicit reference will be made in the remainder of the description) envisages that the bags E are fed towards the conveyor 4 with the first end (i.e., the one that may possibly carry the sealing line S1) with its direction of maximum extension set horizontally.

[0045] Alternatively, the bags E may be fed towards the conveyor 4 with the aforesaid first end set with its direction of maximum extension set vertically.

[0046] The choice of one or other solution is evidently linked to the relative orientation that it is desired to attribute to the bag E with respect to the product, i.e., with reference to the example of embodiment here illustrated, with respect to the family of planes in which the products comprised in the stack of products P extend.

[0047] In the remainder of the present description it will moreover be assumed that feed of the bags E takes place with the first end (i.e., the one in which the sealing line S1 is possibly present) placed in a front position with respect to the direction of advance of the bags E through the device 1.

[0048] However, as has already been said and as will be better understood in what follows, precisely on account of the conditions of positive control that the device according to the invention is able to exert both on the stacks of products P and on the bags E, the device 1 itself is able to operate even on bags E consisting of tubular lengths still open at both ends.

[0049] At the area or region 5 in which the bags E are fed towards the flow of products P, a divaricating device 6 is provided, which is able to act on the opposite branches of each bag E to divaricate the said branches, the aim being to open each bag E and keep it open in conditions such as to enable insertion therein of the products comprised in the stacks of products P.

[0050] According to the orientation with which the bags are fed towards the device 1, the aforesaid action of divarication may take place either in the vertical direction (as in the case of the example explicitly illustrated) or in the horizontal direction.

[0051] The device 6, which is of a type in itself known, comprises—in a possible embodiment—two plates 7 set opposite one another, with associated thereto suction-type gripping elements (for example, suction-pad formations with associated thereto respective vacuum lines, not illustrated but known in the prior art).

[0052] The aforesaid plates 7 are able to co-operate with the two opposed branches of each bag E, following a general movement of divarication which produces opening of the bag E engaged.

[0053] The divaricating device 6 also performs the function of withholding the bags E, selectively preventing their longitudinal sliding in the general direction of advance of the products whilst the products are being inserted into the bags E, which are kept divaricated. For this purpose, the device 6 may be provided with special hook-like formations, teeth, or retention grooves, etc.

[0054] Once insertion of the products has been completed (according to the modalities better described in what follows), the suction-type retention members associated to the plates 7 can be de-activated so as to leave the bag E containing the products inserted therein free, at the same time enabling advance of the bag E filled with the products towards the closing station 2. This advance takes place under the action of a further motor-driven conveyor, designated as a whole by 8, and basically similar to the conveyor 4.

[0055] Operation of the conveyors 4 and 8 previously cited, of the various elements of the divaricating device 6, as well as of all the other moving elements described herein takes place thanks to members of a motor type which are in themselves known (and hence such as not to call for a detailed description herein) and under the control of a processing unit (not illustrated, but also of a known type). The said processing unit may, for example, be constituted by a so-called programmable logic controller (PLC) or, according to a solution which is becoming increasingly widespread, by an appropriately programmed personal computer (PC).

[0056] The fact of proceeding, according to the criteria of operation here described, to the programming of the processing unit in question corresponds to the carrying-out of a design task that is within the reach of the person skilled in the sector of programming of operation of automatic packaging machines.

[0057] A detailed description of such criteria and modalities of programming is therefore superfluous in the present treatment, also because these criteria and modalities of programming do not, of themselves, constitute an essential element for understanding the invention.

[0058] The reference number 9 designates, as a whole, a pusher device mounted preferably in a position above the conveyor 4 and above the divaricating device 6. The pusher device 9 comprises an active element 10, represented usually by a shovel-like formation capable of acting in a relationship of thrust on the stacks of products P in such a way as to push said stacks of products P into the bags E withheld and kept divaricated in the divaricating device 6.

[0059] The active element 10 of the pusher element 9 in general follows an orbital path having the form of a flattened ring.

[0060] Within the said path, the following may in general be distinguished:

[0061] a bottom stretch or active travel (in this connection, see the sequence of positions P′, P″, P′″ of FIG. 4), in which the active element 10, inserting itself at the back of, or on the rear side of, a respective stack of products P, advances along the direction of advance of the products, pushing the said products into the bag E which is to receive them (the said bag being kept stationary in the divaricating device 6), causing them to advance inside the bag starting from the second end towards the first end; and

[0062] a stretch or return travel, in which the active element 10, having been raised upwards after pushing a stack of products P inside a bag E, returns to its starting position, moving in a direction opposite to the direction of advance of the products, in such a way as to bring itself, after being lowered again, at the back of a new stack of products P to be inserted into a respective bag E.

[0063] The movement of raising the active element 10 upwards (a movement which takes place between completion of the active travel forwards and start of the return travel backwards) is not in general prevented by the bags E.

[0064] In fact, operation of the divaricating device 6 and of the additional conveyor 8 is synchronized with the movement of the pusher element 9 in such a way that the device 6, as soon as the movement of insertion of the products is completed, releases the bag E into which the said products have just been inserted.

[0065] The bag in question starts, then, to advance on the conveyor 8, disengaging itself (in practice, sliding out) with respect to the active element 10 of the pusher device 9.

[0066] The aforesaid result may be simply obtained by programming (in a way of itself known) the control unit which monitors operation of the device 1 and in particular superintends control of the movement of the pusher element 9 and of the divaricating device 6.

[0067] The instant at which the movement of insertion of the stacks of products P inside the bags E terminates is therefore determined solely by the relative position of the elements involved in this action.

[0068] Completion of the movement of insertion is therefore in itself not linked to the fact that the stack of products P inserted in the bag E comes actually to bear upon, or into a relationship of pushing against, the bottom wall, which is usually already present, at the first end of said bag E.

[0069] This fact is important for at least three reasons, as described in what follows.

[0070] In the first place, it is possible to prevent the products of the stack of products P, at least in particular operating conditions, from exerting a thrusting action that is too strong and violent against the aforesaid first end of the bag E, with the consequent risk of damaging it or, in any case, of bestowing thereon an undesired swollen or rounded shape.

[0071] In the second place, it is possible, where desired, to co-ordinate the movement of the pusher device 9 with the action of temporary retention of the bags E exerted by the divaricating device 6 in such a way that, in their movement of advance, the products of the stack of products P do not arrive right up against the first end of the bag E. It is thus possible to make packages in which the products of the stack of products P are received in a rather loose and non-adherent way inside the bag E.

[0072] In the third place, precisely for the reason just mentioned, the solution according to the invention is also suited to being used in conjunction with bags E which, at the moment when the products of the stack of products P are inserted inside them, are simply tubular lengths open at both ends and designed to be closed only subsequently, for example, with the formation of the sealing lines S1 and S2 at the first end and at the second end, respectively.

[0073] In the currently preferred embodiment of the invention, it is envisaged that, when the divaricating device 6 releases the bags E, each of which contains a respective stack of products P, the said bags E have in general the conformation represented in FIG. 1, with the first end (downstream in the direction of advance through the device 1) already closed, and the second end still open and to be closed, with formation of the line S2, in the station 3.

[0074] As has already been said, at the moment when the divaricating device 6 releases the bag E with the corresponding products inserted therein, the bag E in question is recalled forwards by the conveyor 8, sliding away from the active element 10 of the pusher device 9. The latter can thus return from the position of maximum advance (represented by the solid line in FIG. 4) to the position of maximum back-off (represented by the dashed line in FIG. 4), thus being able again to perform a thrusting action on a subsequent stack of products in the movement of advance which comprises the intermediate position represented by a dashed-and-dotted line again in FIG. 4.

[0075] It will moreover be appreciated that, in the movement of return from the position of maximum advance to the position of maximum back-off, the pusher device 9 is at least slightly raised so as not to interfere with the movement of advance of the subsequent stack of products that advances towards the area of insertion in the bag, and, before that, so as not to interfere with the bags E that are positioned to receive the products. The aforesaid orbital movement (consisting of the superposition of a movement of advance/back-off and of a movement of lowering/raising) takes place under the action of a motor device, associated to which is a corresponding mechanism usually of the cam type.

[0076] The ensemble made up of the aforesaid motor and the corresponding mechanism, designated as whole by 11 in FIGS. 3 and 4, corresponds to a solution in itself known, also in the sector of packaging equipment. A detailed description of the corresponding structure is therefore altogether superfluous herein.

[0077] Passing on to an examination of the structure of the closing station 3, it will be noted in the first place that the said structure is mounted on a disk structure 12 that is able to rotate about a respective main axis X12. The axis X12, here oriented in a horizontal direction, corresponds in practice to the main central axis of the path of advance of the products P (see the view of FIG. 5).

[0078] The aforesaid movement of orientation of the structure 12 about the axis X12 is performed between a horizontal operating position (namely the one represented in FIG. 5) and a vertical operating position. The latter position is reached by means of a movement of rotation having an amplitude of 90° about the axis X12 under the action of a motor-driven member consisting, for example, of an actuator 12 a controlled by a motor or, even more simply, in a manual way, for instance by means of a handle 12 b.

[0079] The fact that the closing station 3 is set in the horizontal operating position or else in the vertical operating position identifies the orientation that it is desired to impart to the sealing line S2 that is to be formed in the part upstream (of course, once again with reference to the direction of advance of the products through the device 1) of the final package.

[0080] It will moreover be appreciated that the closing station 3 may in effect be placed also in any intermediate position between the aforesaid horizontal and vertical end positions. This means that, if so desired and if such a condition is compatible with the other characteristics of the bag E, the line S2 may be made with any orientation comprised between the horizontal orientation and the vertical orientation.

[0081] In a way of itself known, the closing station 3 comprises a pair of jaws 13, which can move selectively between one divaricated position (the one represented in FIG. 5) and a gripping or closing position in which, as a result of a combined and simultaneous movement of lowering of the jaw 13 that is in the top position and of raising of the jaw 13 that is in the bottom position, the said jaws 13 close one against another with the interposition of the film of the bag E, so causing closing and sealing thereof, this being obtained of course by acting in areas of the bag E in which products are not present.

[0082] The sealing effect is typically achieved by heating of the jaws 13 (for this purpose the jaws 13 may be equipped with corresponding electrical resistors for heating not shown) such as to bring about a local heat sealing of the material making up the bags E.

[0083] Also known in the prior art are other solutions (for instance, sealing by the application of bonding material, ultrasound sealing, etc.).

[0084] This also applies to the motor-powered assemblies that control the movement of the jaws 13. Partially visible in the view of FIG. 3 is a belt drive 14 comprised in the mechanism for actuating the jaws 13 according to a configuration that enables a displacement for controlling movement of closing/divarication of the jaws 13 both in the case where the closing station 3 is in the horizontal operating position and in the case where the closing station 3 is in the vertical operating position, as well as in the case where the closing station 3 is located in any position between the two aforesaid horizontal and vertical operating positions.

[0085] The reference number 15 designates two lateral forming elements, each of which has in its distal portion an overall arrow-like configuration.

[0086] The elements 15 are designed to converge (under the action of actuating means—not shown—which may correspond at least in part to the means for actuating the jaws 13) towards the area of intervention of the jaws 13 themselves so as to bring about the formation of bellows-like formations B2 associated to the sealing line S2 (see once again FIG. 2).

[0087] The entire foregoing description of the structure and modes of operation both of the jaws 13 and of the forming elements 15 corresponds to constructional concepts that are well known to the prior art and such as not to call for any detailed description herein.

[0088] The general movement of orientation of the disk platform 12 about the axis X12 enables rotation of the closing station to bring it selectively into any of the following positions:

[0089] in the horizontal operating position represented in FIG. 5, where the jaws 13 perform a closing movement in the vertical direction, whilst the forming elements 15 converge towards the closing area of the jaws 13, moving in the horizontal direction;

[0090] in the vertical operating position, schematically represented with a dashed line in FIG. 5, where instead it is the jaws 13 that close one against the other as a result of a movement in the horizontal direction, whilst the forming elements 15 converge towards the closing area of the jaws 13 as a result of a lowering/raising movement in the vertical direction; and

[0091] in any angular position between the said horizontal position and the said vertical position.

[0092] When the closing station 3 is set in the horizontal operating position, the sealing line S2 is oriented in the horizontal direction. When, instead, the closing station 3 is set in the vertical operating position, the sealing line S2 is oriented in the vertical position.

[0093] By means of a simple operation of adjustment (which can be easily performed by an operator) it is thus possible to set the device 1 in the pre-chosen operating position.

[0094] Usually, when the bags E are fed from the station F to the device 6 with their direction of greater extension oriented in the horizontal direction, the closing station 3 is regulated in the horizontal operating position.

[0095] Conversely, when the bags E are fed towards the device 6 with their direction of greater extension oriented in the vertical direction, the closing station 3 is brought, by rotation of the disk platform 12, into the vertical operating position.

[0096] It is of course possible to operate in also a dual way, that is, to feed the bags E with their direction of greater extension oriented in the horizontal direction and then regulate the closing station 3 in such a way as to form the other sealing line S2 oriented in the vertical direction, or conversely feed the bags E with their direction of greater extension oriented in the vertical direction, and then set the closing station 3 in the horizontal operating position so as to obtain the sealing line S2 oriented in the horizontal direction.

[0097] In this way it is, for example, possible to make packages in which the sealing lines S1 (if present) and S2 lie in planes that are mutually orthogonal, at the same time maintaining the general transverse orientation with respect to the direction of advance of the products (axis X12), or again make packages in which the sealing line S2 is skew with respect to the package as a whole. The foregoing may of course be achieved by intervening appropriately, and in accordance with known technical criteria, on the mechanism of formation of the bellows-like formations B1 and/or B2.

[0098] As may be better noted in the elevation of FIG. 4, the conveyor 8 terminates immediately upstream of the area in which the jaws 13 of the closing station 3 act.

[0099] As the bags E pass towards the closing station 3 to be subjected to the formation of the sealing line S2, the said bags E (which contain the stacks of products P) are transferred onto yet another conveyor 16, which usually presents a structure substantially resembling the structure of the conveyors 4 and 8 referred to previously.

[0100] The said conveyor may, for instance, be a conveyor comprising three motor-driven belts the active branches of which respectively define the side walls and the bottom wall of the conveyor.

[0101] This is of course only one of the possible choices, given that (it will be noted that these considerations apply moreover also to the conveyors 4 and 8) it is possible to resort, for instance, to solutions in which the conveying structures are different from motor-driven belts, or else to solutions in which only the bottom wall or else only the side walls of the conveyor are effectively motor-driven and hence mobile.

[0102] The above considerations are on the other hand evident to the person skilled in the sector without any need for further explanations or clarifications.

[0103] From FIG. 4, and in particular from the part furthest to the left in the drawing, it may be noted that, in the currently preferred embodiment of the invention, the end upstream 16 a of the conveyor 16 is built in such a way that at least one, and preferably all, of the belts comprised in the conveyor 16 has an end upstream that is selectively translatable by means of the operation of a control assembly 17. The latter may for example be a crank mechanism driven by a motor element not specifically illustrated in the drawings.

[0104] In the representation of the conveyor 16 shown in FIG. 4, persons skilled in the sector will recognize immediately the presence of a tensioning roller or mobile jockey pulley 18 the function of which is to compensate for the variation in length of the conveying stretch of the conveyor 16 resulting from the displacements of the end upstream 16 a.

[0105] In particular, the movement of the aforesaid end upstream 16 a takes place between:

[0106] a backed-off position (with respect to the area of intervention of the jaws 13), represented by a solid line in FIG. 4, where the end upstream 16 a of the conveyor 16 is backed off, and hence disengaged from the region of intervention of the jaws 13; and

[0107] an advanced or forward position (represented by a dashed line in FIG. 4) in which the end upstream 16 a of the conveyor 16 is projected towards the conveyor 8 extending through the area of intervention of the jaws 13.

[0108] The unit that monitors the operation of the equipment as a whole is programmed (in a way of itself known) in such a manner that, when a bag E containing a stack of products P is released from the pusher device 6 and, advancing on the conveyor 8, moves into the vicinity of the end downstream of the conveyor 8, the end upstream 16 a of the conveyor 16 is brought into the advanced or forward position in such a way as to be able to receive the aforesaid bag E.

[0109] The above procedure prevents the package that is being formed, as it passes from the conveyor 8 to the conveyor 16, from having to cross an appreciable discontinuity of the conveying structure. In other words, in the conditions described, the conveyor 8 and the conveyor 16 practically extend, cascaded together, with a minimal discontinuity: in this connection, see the minimal distance that separates the roller or return idlers that occupy the position furthest downstream of the conveyor 8 from the end upstream 16 a of the conveyor 16, represented by a dashed line.

[0110] Setting itself with its end upstream 16 a stretching forwards towards the conveyor 8, the conveyor 16 goes to pick up, so to speak, the bags E with the corresponding products P arriving on the conveyor 8.

[0111] The conveyor 16 then moves, as soon as the bag in question has reached the end upstream 16 a of the conveyor 16, into the backed-off position in which the end upstream 16 a of the conveyor 16 disengages the area of intervention of the jaws 13. The jaws 13 can then close on the upstream end of the bag E (i.e., the end represented in the right-hand part of FIG. 1) so as to close it and thus give rise to the sealing line S2 and to the bellows-like formations B2 (in this case see the right-hand part of FIG. 2).

[0112] In the currently preferred embodiment of the invention it is envisaged that the conveyor 16—and the bag E that is on the said conveyor at the end 16 a to be exposed to the action of the jaws 13—may be controlled so that it advances slightly (this is in actual fact, with reference to the direction of advance of the products and of the packages, a backing-off) towards the conveyor 8 during the movement of closing of the jaws 13.

[0113] This is of course achieved without any interference with the movement of closing of the jaws 13 but at the same time preventing the said closing movement from possibly giving rise to undesired or anomalous stresses of the sheet material that constitutes the bag E precisely in the area in which the sealing area S2 is to be formed.

[0114] For further clarification, see again FIG. 1, in the left-hand part of which are schematically represented and designated by L13 the two areas in which the jaws 13, in their closing movement, encounter the sheet material of the bags E.

[0115] It may at once be realized that, as a result of the closing movement of the jaws 13, which proceeds until the latter are closed against one another with the interposition of the sheet material, the areas L13 end up by coming right up against the body of the package (that is, the region occupied by the products P); the regions designated by L13 are in fact precisely the regions of the bag E that are to form a large part of the sealing line S2.

[0116] The above fact could lead to at least two negative consequences, as described in what follows.

[0117] If the gripping action of the jaws 13 on the sheet material of the bag E is particularly forceful (for example, because the jaws 13 immediately heat the sheet material, which is thus quite firmly anchored to the jaws 13), the closing movement of the jaws against one another might lead to a movement of return of the entire bag in the direction of the vertical plane, where the jaws 13 close against one another.

[0118] As a result, when the jaws close against each other, they end up by pulling back towards them (in a movement towards the right) the entire package that is being formed.

[0119] Since the said package is in itself withheld by the conveyor 16 (which remains in general stationary whilst the jaws 13 are acting), the gripping action of the jaws 13 on the sheet material may end up leading to an undesired stretching of the sheet material of the bag in the area that is closed up against the stack of products P to form the sealing line S2.

[0120] Taking into account also the fact that this area of sheet material is at least partially subjected to heating by the jaws, there exists the risk that the package may get damaged in an undesired manner.

[0121] According to the same mechanism, even though the jaws 13 do not in themselves perform a very firm gripping action on the sheet material of the bags E (for instance, the case where the jaws 13 form the sealing lines S2 by ultrasound sealing, with the corresponding sonotrodes activated only when the jaws are in the closing position), there will in general be a movement of relative sliding between the sheet material of the bag E and the jaws 13.

[0122] However, it may well happen that the said sliding phenomenon occurs in a different way in the case of the first jaw 13 which is descending from the way it does in the case of the second jaw 13 which is rising, the operation taking place in such a way that the sealing line S2 ends up being made in an area that is not exactly centred with respect to the finished package.

[0123] The controlled reverse movement of the conveyor 16 (which may possibly be replaced by a reverse displacement of the end 16 a, controlled by the mechanism 17 according to the modalities described previously) instead enables prevention of the aforesaid negative phenomena.

[0124] In practice, as soon as the jaws 13 come into contact with the areas designated by L13 in FIG. 1, the conveyor 16 is activated in such a manner as to cause a slight and gradual backing-off of the package (i.e., the bag E with the products P inside) which is on the end 16 a towards the area in which the jaws 13 act.

[0125] The movement thus imparted on the package is such as to compensate the aforesaid movement of folding of the sheet material such as to cause the areas L13, which are initially at a distance from the stack of products P (see FIG. 1), to end up coming right up against the stack of products P itself so as to give rise to the sealing line S2 (now see FIG. 2).

[0126] In particular, the reverse movement of the conveyor 16 is controlled in a way exactly coordinated with the movement of closing of the jaws 13, in such a manner that, as the jaws 13 are advancing towards one another, squeezing between them the sheet material (which, with the package held firm, would lead either to an undesired tension and/or an equally undesired sliding of the sheet with respect to the jaws 13), the package being formed is made to back up gradually towards the said jaws.

[0127] The reverse movement of the conveyor 16 thus makes it possible, even though the plane in which the jaws 13 move remains vertical, for the body of the package represented by the stack of products P to be caused to move gradually backwards towards the aforesaid plane.

[0128] This happens with a speed of movement linked to the speed of movement of the jaws 13 according to the geometry of the package, and in particular linked to the thickness of the package, measured in the direction of closing of the jaws 13).

[0129] In this way there is no relative displacement between the active surfaces of the jaws 13 and the respective regions of the sheet material on which the jaws act.

[0130] This fact is illustrated in FIG. 1, where the sectional profile of a jaw 13 is represented (here reference is made to the top jaw, but the same applies equally to the bottom jaw) which initially comes into contact with the sheet material of the bag E in the area L13 and then descends vertically until it forms the sealing area S2, at the same time, however, always remaining in contact with the area L13, i.e., maintaining substantially constant the position in which the closing elements (here represented by the jaws) co-operate with the sheet material constituting the bags E.

[0131] Of course, without prejudice to the principle of the invention, the details of implementation and the embodiments may vary widely with respect to what is described and illustrated herein, without thereby departing from the scope of the present invention as defined in the annexed claims. This applies in particular to the possible application of the invention to the packaging of products different from the ones illustrated. The products packaged may, for instance, be individual products that are not set in stacks, and/or products other than ones having a flattened shape. 

1. A process for packaging products in which the products being packaged are placed inside bags and subjected to the action of a pusher element acting in a pushing region for pushing said products towards a closing region in which at least one closing element grips said bags containing said products in at least one area of the bags in which the products are absent, wherein said pushing region and said closing region are separate from one another, so that said pusher element is kept disengaged from said closing region.
 2. The process of claim 1, comprising the operations of: feeding said products through said pushing region and said closing regions, which are arranged in cascaded fashion; withholding said bags in said pushing region whilst said pushing element pushes said products into said bags; and then releasing said bags, enabling advance of said bags towards said closing region and disengagement from said pusher element.
 3. The process of claim 1 comprising the operations of: providing in said bags a first end and a second end; inserting said products in said bags, causing them to advance, by means of said pusher element, from said second end towards said first end.
 4. The process of claim 3, wherein said products are made to advance to come into close proximity of said first end.
 5. The process of claim 3, wherein said products are made to advance up to a certain distance from said first end.
 6. The process of claim 3 comprising the operation of providing said bags, before insertion of said products in them, with a first closed end.
 7. The process of claim 3 comprising the operation of forming, by means of said at least one closing element, a sealing line in said second end of said bags so as to close said products in them.
 8. The process of claim 7 comprising the operations of: arranging said bags with said first end oriented in a given direction; and making said at least one closing element selectively orientable, about a respective axis of orientation, so that said sealing line can be made with a spatial orientation selectively determined with respect to said first end.
 9. The process of claim 7, wherein said products advance according to a general direction of advance and said sealing line is oriented in a direction substantially orthogonal to said direction of advance.
 10. The process of claim 1, wherein said products are made up of stacks of articles having a generally flattened shape and are such as to identify a respective family of planes of extension.
 11. The process of claim 9, wherein said products are made up of stacks of articles having a generally flattened shape and are such as to identify a respective family of planes of extension and further wherein said sealing line is orthogonal to said family of planes of extension.
 12. The process of claim 3, comprising the operation of making bellows-like formations in an area corresponding to at least one between said first and second ends of said bags.
 13. The process of claim 12, comprising the operation of making respective bellows-like formations in areas corresponding to both of said first and second ends of said bags, the bellows-like formations associated to said first end being formed so as to extend in a direction longitudinal to said bags, whilst the bellows-like formations associated to said second end are formed so as to extend in a direction transverse to said bags.
 14. The process of claim 1 comprising the operation of imparting on said pusher element a general orbital movement, with a pushing travel in a position of engagement with said products being packaged and a return travel in which the pusher element is disengaged with respect to the path of advance of said products.
 15. The process of claim 1 comprising the operations of: receiving said bags with said products located inside them in a position corresponding to said at least one closing element; issuing a command for the gripping movement of said at least one closing element on said bags; and producing controlled advance of said bags towards the area of intervention of said at least one closing element in a way that is coordinated with the gripping movement of said at least one closing element, basically maintaining the position of co-operation of said at least one closing element with said bags constant.
 16. The process of claim 1 comprising the operations of: conveying said bags containing said products respectively upstream and downstream of said at least one closing element by means of a respective first conveyor and a respective second conveyor; and rendering the end upstream of said second conveyor selectively movable between: a stretched-forward position for receiving the bags, in which said end upstream is brought in close proximity to said first conveyor to receive said bags, said end upstream extending through the area of intervention of said at least one closing element; and a back-off position, in which said end upstream with said bags received on it moves away from said respective first conveyor, disengaging the area of intervention of said at least one closing element.
 17. A device for packaging products, comprising: a unit for receiving bags for packaging said products, said unit being able to bring said bags into the opening position; a pusher element for acting in a respective pushing region on said products placed in said respective bags; and at least one closing element towards which said pusher element pushes said products; said at least one closing element acting in a respective closing region to grip said bags containing said products in areas of said bags where said products are absent wherein said pusher element and said at least one closing element act in respective regions that are separate from one another, so that said pusher element is kept disengaged from the region in which said at least one closing element acts.
 18. The device of claim 17, comprising: conveyor elements to cause said products to advance through said pushing region and said closing region; at least one retention element able to withhold said bags kept in the opening position while said pusher element is pushing said products inside said bags; said retention device being configured for subsequently releasing said bags which advance being moved by said conveyor elements towards said closing region, disengaging said pusher element.
 19. The device of claim 17 wherein said pusher element carries associated thereto an actuation mechanism adapted for imparting to the pusher element itself: an active pushing travel, in which said pusher element acts on said products, pushing them inside said bags; and a return travel, in which said pusher element is disengaged with respect to the path of advance of said products.
 20. The device of claim 17 comprising, in a position upstream of said pushing region, a stacking device to set said products in the form of stacks of individual articles defining a family of respective planes of extension.
 21. The device of claim 17, wherein said at least one closing element is adapted for acting on said respective bags to form at least one respective sealing line oriented in a pre-set direction.
 22. The device of claim 21, wherein said at least one closing element comprises two jaws adapted to close selectively on said bags to form said at least one sealing line.
 23. The device of claim 21, wherein said at least one closing element carries, associated thereto, at least one forming element adapted for moving concordantly with said at least one sealing line, advancing towards said bags so as to form, in the proximity of said at least one sealing line, at least one respective bellows-like formation.
 24. The device of claim 21, wherein said at least one closing element is mounted on a mobile piece of equipment selectively orientable so as to vary selectively the direction of extension of said at least one respective sealing line.
 25. The device of claim 17, wherein: the device defines a main axis of advance of said products being packaged; said at least one closing element acts in a direction transverse to said main direction of advance.
 26. The device of claim 24, wherein: the device defines a main axis of advance of said products being packaged; said at least one closing element acts in a direction transverse to said main direction of advance, and wherein said mobile piece of equipment is selectively orientable about said main axis of advance.
 27. The device of claim 25, wherein: a device is provided for feeding said bags, said device being arranged for feeding bags oriented in at least one first direction and one second direction that are orthogonal to one another; and said mobile piece of equipment is selectively orientable between at least one respective first operating position and at least one respective second operating position, so that said at least one closing element is able to form said at least one respective sealing line selectively in said first direction and in said second direction orthogonal to one another.
 28. The device of claim 24, wherein said at least one mobile piece of equipment is substantially configured in the form of a circular platform which is adapted to rotate about an axis.
 29. The device of claim 17 comprising at least one conveyor with one end located in the proximity of said at least one closing element, said at least one conveyor carrying, associated thereto, control means that enable said at least one conveyor to be moved selectively towards said at least one closing element in a way that is coordinated with the gripping movement of said closing element, keeping the position of co-operation of said at least one closing element with said bags substantially constant.
 30. The device of claim 17 comprising: a first conveyor and a second conveyor respectively upstream and downstream of said at least one closing element in the direction of advance of said products, wherein said second conveyor is provided with one end set upstream, to which are associated adjustment means for causing displacement of said ends upstream between: a forward position of reception of said bags, in which said end upstream extends in a relationship of close proximity towards said first conveyor through the closing region in which said at least one closing element acts; and a back-off position in which said end upstream of said second conveyor is able to receive said bags undergoing the action of said at least one closing element in the absence of interference with the movement of said at least one closing element. 